Uninterruptable power supplies used to provide a reliable and continuous source of alternating electrical energy to one or more electrical devices, such as pumps or computer systems, have become more and more important as computers, networks, and other devices, whose reliable and continuing performance is required, have spread throughout the industrial world. One known form of uninterruptable power supply utilizes a pair of switching elements in combination with a ferroresonant transformer.
While such products have been successful, they often require a special transformer, which can add substantially to the overall price of the unit. In addition, such devices tend to have a single function. That function is one of providing a source of alternating current electrical energy in response to a failure of utility supplied energy.
There continues to be a need for high performance, low cost, uninterruptable power supplies given the wide range of demands for such service. Preferably, such supplies would be less expensive than known supplies which use custom ferroresonant transformers. Also preferably, it would be desirable to be able to organize such a supply on a modular basis, such that additional power modules could be added to provide differing electrical output characteristics.
It would be desirable to be able to use the same circuitry that generates the output AC to recharge the associated batteries.